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Columbus Duct Installation Contractors

Feb 14

How to Design an Industrial Ducting System. - Duct Velocities

You should ensure that your ducting system is as efficient and cost-effective as possible, whether you are looking for Columbus Duct Installation Contractors or modifying one. It can be expensive to install and maintain ducting systems. Your bottom line is dependent on making sure you only purchase what you actually need. Columbus Airduct Cleaning can help you make accurate calculations based upon your dust velocity.

How to determine dust velocity

The type of material being transported within ductwork determines the velocity. The diameter of the duct determines the airflow, which is measured in cubic feet per hour (cfm). To prevent particulate particles from settling in the duct and dropping out of the airstream, systems that handle them must have a minimum design velocity. A high velocity can cause duct damage and power waste.

This equation defines the relationship between airflow (Q), duct velocity (v), and diameter (d).

Q = A * v, where A = p * d2 / 4 or,


Q = (p * d2 / 4) * v

This equation can be used to calculate the required Air Flow (Q), for a given duct diameter (d) and duct velocity (v). If you find that the duct velocity of 4000 feet per hour (fpm), is required in a 9-inch (0.75ft.) diameter conduit, the amount you would require for airflow would be:

Q = (p * (0.75 ft.)2 / 4) * (4000 ft./min) = 562.5 cfm

The equation can be used to determine the velocity (v), in a system with an Air Flow(Q) through a section duct with diameter.

v = (4 * Q) / (p * d2)

If a fan produces 600 cfm, the velocity of air passing through a 6-inch duct would be: The diameter of a duct measuring 0.5 feet would be:

v = (4 * 600) / (p * (0.5)2) = 3056 fpm

The equation is used to determine the diameter of the duct required to achieve a velocity (v), for a fan that provides a specific airflow (Q).

d = (4 * Q) / (p * v)

The duct diameter needed for 4000 fpm velocity would be required in a system with a 1000 cfm airflow.

d = (4 * 1000) / (p * 4000) = 0.564 feet or 6.77 inches

To achieve 4000 fpm velocity you will need to round up to the nearest standard duct size or 6-inch diameter.

You will save both time and money by using precise dust velocity calculations. This will allow you to ensure that your ducting system runs at its full potential.


Columbus Airduct Cleaning

Columbus, OH

(740) 291 0950